Calculate bytes per second in network gauges

// FREEBIE

src/main/java/org/whispersystems/textsecuregcm/metrics/NetworkGauge.java

@@ -9,7 +9,7 @@ import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
 
-public abstract class NetworkGauge implements Gauge<Long> {
+public abstract class NetworkGauge implements Gauge<Double> {
 
   protected Pair<Long, Long> getSentReceived() throws IOException {
     File           proc          = new File("/proc/net/dev");

src/main/java/org/whispersystems/textsecuregcm/metrics/NetworkReceivedGauge.java

@@ -13,23 +13,31 @@ public class NetworkReceivedGauge extends NetworkGauge {
   private long lastTimestamp;
   private long lastReceived;
 
+  public NetworkReceivedGauge() {
+    try {
+      this.lastTimestamp = System.currentTimeMillis();
+      this.lastReceived  = getSentReceived().second();
+    } catch (IOException e) {
+      logger.warn(NetworkReceivedGauge.class.getSimpleName(), e);
+    }
+  }
+
   @Override
-  public Long getValue() {
+  public Double getValue() {
     try {
       long             timestamp       = System.currentTimeMillis();
       Pair<Long, Long> sentAndReceived = getSentReceived();
-      long             result          = 0;
+      double           bytesReceived   = sentAndReceived.second() - lastReceived;
+      double           secondsElapsed  = (timestamp - this.lastTimestamp) / 1000;
+      double           result          = bytesReceived / secondsElapsed;
 
-      if (lastTimestamp != 0) {
+      this.lastTimestamp = timestamp;
-        result       = sentAndReceived.second() - lastReceived;
+      this.lastReceived  = sentAndReceived.second();
-        lastReceived = sentAndReceived.second();
-      }
 
-      lastTimestamp = timestamp;
       return result;
     } catch (IOException e) {
       logger.warn("NetworkReceivedGauge", e);
-      return -1L;
+      return -1D;
     }
   }
 

src/main/java/org/whispersystems/textsecuregcm/metrics/NetworkSentGauge.java

@@ -13,23 +13,31 @@ public class NetworkSentGauge extends NetworkGauge {
   private long lastTimestamp;
   private long lastSent;
 
-  @Override
+  public NetworkSentGauge() {
-  public Long getValue() {
     try {
-      long             timestamp       = System.currentTimeMillis();
+      this.lastTimestamp = System.currentTimeMillis();
-      Pair<Long, Long> sentAndReceived = getSentReceived();
+      this.lastSent      = getSentReceived().first();
-      long             result          = 0;
+    } catch (IOException e) {
+      logger.warn(NetworkSentGauge.class.getSimpleName(), e);
+    }
+  }
 
-      if (lastTimestamp != 0) {
+  @Override
-        result        = sentAndReceived.first() - lastSent;
+  public Double getValue() {
-        lastSent      = sentAndReceived.first();
+    try {
-      }
+      long             timestamp        = System.currentTimeMillis();
+      Pair<Long, Long> sentAndReceived  = getSentReceived();
+      double           bytesTransmitted = sentAndReceived.first() - lastSent;
+      double           secondsElapsed   = (timestamp - this.lastTimestamp) / 1000;
+      double           result           = bytesTransmitted / secondsElapsed;
+
+      this.lastSent      = sentAndReceived.first();
+      this.lastTimestamp = timestamp;
 
-      lastTimestamp = timestamp;
       return result;
     } catch (IOException e) {
       logger.warn("NetworkSentGauge", e);
-      return -1L;
+      return -1D;
     }
   }
 }